<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuWrapper">
      <ul>
        <li v-for="item,index in goods" class="menu-item" :class="{'current':currentIndex === index}"
            :key="index" @click="selectMenu(index,$event)">
          <span class="text border-1px">
            <icon v-show="item.type>0" class="icon" :size="3" :iconType="item.type"></icon>{{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <li class="food-list food-list-hook" v-for="item,index in goods" :key="index">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li v-for="food,index in item.foods" :key="index" class="food-item border-1px" @click="selectFood(food,$event)">
              <div class="icon">
                <img width="57" height="57" :src="food.icon" />
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span><span class="rating">好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}</span><span v-show="food.oldPrice" class="old">￥{{food.oldPrice}}</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <cartcontrol :food="food" @add="_drop"></cartcontrol>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shopcart  ref="shopcart" :selectFoods="selectFoods" :deliveryPrice="seller.deliveryPrice" :minPrice="seller.minPrice"></shopcart>
    <food :food="selectedFood" ref="food" @add="_drop">

    </food>
  </div>
</template>

<script type="text/ecmascript-6">
  import icon from '../../components/icon/icon.vue';
  import shopcart from '../../components/shopcart/shopcart.vue';
  import cartcontrol from '../../components/cartcontrol/cartcontrol.vue';
  import food from '../../components/food/food.vue';
  import BScroll from 'better-scroll';
  const ERR_OK = 0;
  export default {
//    得到父组件的数据
    props: {
      seller: {
        type: Object
      }
    },
//    Vue 实例的数据对象
//    当一个组件被定义， data 必须声明为返回一个初始数据对象的函数，因为组件可能被用来创建多个实例
    data() {
      return {
        goods: [],
        listHeight: [],
        scrollY: 0,
        selectedFood: {}
      };
    },
//    计算属性
    computed: {
      currentIndex() {
        for (let i = 0; i < this.listHeight.length; i++) {
          let height1 = this.listHeight[i];
          let height2 = this.listHeight[i + 1];
          if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
            return i;
          }
        }
        return 0;
      },
      selectFoods() {
        let foods = [];
        this.goods.forEach((good) => {
          good.foods.forEach((food) => {
            if (food.count) {
              foods.push(food);
            }
          });
        });
        return foods;
      }
    },
//    实例已经创建完成之后被调用
    created() {
      this.$http.get('/api/goods').then((response) => {
        response = response.body;
        if (response.errno === ERR_OK) {
          this.goods = response.data;
          this.$nextTick(() => {
            this._initScroll();
            this._calculateHeight();
          });
        };
      });
    },
//    方法
    methods: {
      selectMenu(index, e) {
//        当better-scroll 派发的点击事件不存在时（即pc端），不做处理
        if (!e._constructed) {
          return;
        }
        let foodlist = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
//        拿到相应的dom元素
        let el = foodlist[index];
//        scrollToElement(el, time, offsetX, offsetY, easing)
//        滚动到某个元素，el（必填）表示 dom 元素，time 表示动画时间，
//        offsetX 和 offsetY 表示坐标偏移量，easing 表示缓动函数
        this.foodsScroll.scrollToElement(el, 300);
      },
      selectFood(food, e) {
//        当better-scroll 派发的点击事件不存在时（即pc端），不做处理
        if (!e._constructed) {
          return;
        }
        this.selectedFood = food;
        this.$refs.food.show();
      },
      _drop(target) {
//        体验优化，异步执行下落动画
        this.$nextTick(() => {
          this.$refs.shopcart.drop(target);
        });
      },
      _initScroll() {
        this.menuScroll = new BScroll(this.$refs.menuWrapper, {
          click: true
        });
        this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
          click: true,
          probeType: 3
        });
        this.foodsScroll.on('scroll', (pos) => {
//          获取滚动的y坐标
          this.scrollY = Math.abs(Math.round(pos.y));
        });
      },
      _calculateHeight() {
//        获取每个类型商品的dom对象
        let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook');
        let height = 0;
        this.listHeight.push(height);
        for (let i = 0; i < foodList.length; i++) {
          let item = foodList[i];
          height += item.clientHeight;
          this.listHeight.push(height);
        }
      }
    },
//    组件
    components: {
      icon,
      shopcart,
      cartcontrol,
      food
    }
  };
</script>

<style lang="stylus" rel="stylesheet/stylus">
  @import "../../common/stylus/mixin.styl"
  .goods
    position: absolute
    display: flex
    width: 100%
    top: 174px
    bottom: 46px
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        padding: 0 12px
        height: 54px
        width: 56px
        line-height: 14px
        &:last-child
          .text
            border-none()
        &.current
          position: relative
          background: #fff
          margin-top: -1px
          font-weight: 700
          .text
            border-none()
            font-weight: 700
        .text
          display: table-cell
          width: 56px
          font-size: 12px
          vertical-align: middle
          border-1px(rgba(7,17,27,.1))
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        background-color: #f3f5f7
        font-size: 12px
        color: rgb(147,153,159)
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        border-1px(rgba(7,17,27,.1))
        &:last-child
          border-none()
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          position: relative
          .name
            margin: 2px 0 8px 0
            font-size: 14px
            line-height: 14px
            color: rgb(7,17,27)
            font-weight: bold
          .desc,.extra
            font-size: 10px
            color: rgb(147,153,159)
            line-height: 10px
          .desc
            margin-bottom: 8px
            line-height: 12px
          .extra
            .count
              margin-right: 12px
          .price
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240,20,20)
              font-weight: 700
            .old
              font-size: 10px
              color: rgb(147,153,159)
              text-decoration: line-through
              font-weight: 700
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: -6px
</style>
